1. Field of the Invention
The present invention relates to an image processing method and apparatus, and more particularly to an image processing method and apparatus for discriminating the input image area or the attribute of image information in the discriminated area.
2. Related Background Art
In conventional image processing apparatuses, the image in an original having a plurality of different attributes such as text, graphic or icon mixed, or an original having only one attribute but divisible into a plurality of areas was processed to designate the area or the attribute of image information in the discriminated area from the image of each original, which was allowed only in terms of the specifications in some way from the user""s hand.
This specification by the user""s hand may include:
1) Setting an original on the image reader such as a scanner,
2) Issuing an instruction to read the image of its original from the host computer connected to the image processor,
3) Prescanning the image upon its instruction to display temporarily the input image on the display screen of the host computer,
4) Inputting the information of the area of image attributes for the image displayed temporarily, using a mouse or keyboard by the user""s hand, and
5) Scanning the original in accordance with the area information or the attribute information which has been input to store the input image data.
Still further, the image data incorporated may be subjected to character recognition processing or image compression processing which is a processing suitable for the attribute designated in each area.
However, with the above conventional method, for a variety of sorts of originals which could be input, the designation of the area, or the attributes, by the user""s hand was required every time the original image was processed, so that the user""s burden was enormous, which made it difficult to process a large amount of original image.
Also, conventionally, a simple area discriminating method with longitudinal and transversal oblique shadow (histogram analysis) was employed as the image area separation technique of automatically discriminating the character (text) area or the image area from input image data without intervention of the user""s hand.
However, with this method, the discrimination accuracy was lower, depending on the original condition, owing to the difficulty of discrimination between the character area with relatively more white pixels and the image area.
Also, conventionally, in discriminating the area or attribute of the image, the discrimination accuracy was sometimes degraded due to the noise contained in the input image data.
According to the present invention, each area surrounded by feature pixels within the image data read by predetermined reading means is chased one pixel after another to extract the feature of the area, whereby an intelligent function is added to an image reading process of an image recognition device to extend significantly its utilization form and relieve the human""s burden, thereby achieving an improved recognition rate of image data.
According to the present invention, at the time when the feature pixel is detected on the basis of a raster scan method which starts from one end of the image data, the contour of an area to which the feature pixels belong is chased to extract the feature of the area, whereby all the feature pixel blocks in the image data can be detected by repeatedly performing the raster scan in such a way as to chase the contour from the start point of the first detected feature pixel among a feature pixel block to be detected and back to the start point again, thereby providing the information for the accurate area discrimination.
According to the present invention, the contour of an area surrounded by background pixels within the area surrounded by feature pixels is further chased, and the chasing of the contour of the area surrounded by feature pixels and the chasing of the contour of the area surrounded by background pixels are alternately repeated, whereby the contour of e.g., a character in the table can be detected.
According to the present invention, the chasing of the contour is sequentially performed, starting from an adjacent pixel lying in the synthesized direction of the direction opposite to a scan direction of short period with the raster scan method and a scan direction of long period with the raster scan method, in a direction toward an adjacent pixel in said scan direction of long period, or starting from an adjacent pixel in said scan direction of short period with the raster scan method, in a direction toward an adjacent pixel in the synthesized direction of said scan direction of long period with the raster scan method and said scan direction of short period, whereby the detection of feature pixels around a noticed pixel is given the order of priority, and if a higher priority pixel is detected, the raster scan immediately moves to its position to detect a feature pixel block with a minimum amount of investigation as required, so that the detecting process can be speeded up.
According to the present invention, even with the noise contained in the input image, the noise can be removed at high accuracy, so that the subsequent image processing can be effected at high accuracy without being affected by the noise.